The overall objective of these proposed studies is to advance the development of organ-slice culture technology for application to in vitro animal and human studies in toxicology, pharmacology, and other relevant areas of biomedicine. Specifically, this proposed work is aimed at advancing and refining the methods and instruments to obtain and culture precision-cut thin slices and "microscores" of animal and human organs for greater accuracy and consistency in site-specific toxicologic and pharmacologic studies. Toward these aims, organs would be pre-perfused in situ with a medium designed to protect cells from hypoxic and/or free-radical mediated injuries before they are removed, sliced and placed into culture. They would be cultured in media that also contain protective agents (antioxidants and free radical scavengers). The benefits of such procedures or other steps of the protocol toward the maintenance of cell viability and function will be assessed by cytopathologic, histoenzymologic and biochemical analyses. Another aim relative to specific cell types within the tissue slices is to develop techniques to achieve greater morphologic precision in assessments of cellular viability and intoxication. This aim will be addressed in part through the development and use of cell- and/or site-specific histoenzymologic assays.